Pumping system for liquid hydrocarbons and the like

ABSTRACT

Gasoline or other liquid hydrocarbons are safely, rapidly, and economically pumped from a storage tank to one or more metering dispensers in a vehicle service station by a system including a high-speed air motor compactly arranged in axial alignment with a pump and a motor operating valve assembly of novel construction. The motor is powered by compressed air from a standard source such as found in virtually all vehicle service stations. The air is treated before introduction into the motor and its valve assembly to prevent freeze-jamming of the components during their operation at the high speeds necessary for the attainment of commercially acceptable pumping volumes or gallons per minute. An expansion chamber is preferably provided in series with the discharge line of the pump to dampen the pulsating flow therefrom and thus insure relatively uniform flow of liquid to the metering dispenser.

United States Patent Vestal 1 PUMPING SYSTEM FOR LIQUID HYDROCARBONS AND THE LIKE Walter H. Vestal, 820 Silver Avenue, Greensboro, NC. 27403 22 Filed: 0ct.7, 1970 21 Appl.No.: 78,820

[72] Inventor:

[ 51 May 30, 1972 Primary Examiner-Robert M. Walker AttomeyHunt, Heard & Rhodes [57] ABSTRACT Gasoline or other liquid hydrocarbons are safely. rapidly, and economically pumped from a storage tank to one or more metering dispensers in a vehicle service station by a system including a high-speed air motor compactly arranged in axial alignment with a pump and a motor operating valve assembly of novel construction. The motor is powered by compressed air from a standard source such as found in virtually all vehicle service stations. The air is treated before introduction into the motor and its valve assembly to prevent freezejamming of the components during their operation at the high speeds necessary for the attainment of commercially acceptable pumping volumes or gallons per minute. An expansion chamber is preferably provided in series with the discharge line of the pump to dampen the pulsating flow therefrom and thus insure relatively uniform flow of liquid to the metering dispenser.

5 Claims, 14 Drawing figures Patented May 30, 1972 6 Sheets-Sheet 1 WALTER H. VESTAL INVENTOR Patented May 30, 1972 3,665,808

6 Sheets-=Sheet 2 WALTER H. VESTAL INVENTOR Patented May 30,. 1972 6 Sheets-Sheet 4 WALTER H. VESTAL INVENTOR Patented May 30, 1972 3,665,808

6 Sheets-Sheet 6 WALTER H. VESTAL gag/8A 77 INVENTOR FIG. {MI

PUMPING SYSTEM FOR LIQUID I-IYDROCARBONS AND THE LIKE BACKGROUND OF THE INVENTION This invention relates to systems for pumping liquid hydrocarbon such as gasoline, kerosene and like petroleum products from one location to another, and more specifically relates to an improved pumping system especially but not necessarily exclusively adapted for transferring such liquids from an underground storage tank to one or more metering dispensers such as are commonly employed at vehicle service stations where such liquids are sold for use as vehicle fuel.

The pumping systems now generally used for the aforesaid purpose customarily employ electrically operated pumps which are usually submerged beneath the liquids contained within the storage tank from which the transfer is to be made. The pumps, motors and associated wiring must be of complex and expensive construction to minimize insofar as possible the risks of fire, explosion and/or corrosion occasioned by their exposure to the liquids and their vapors. Notwithstanding their attendant disadvantages of danger, cost and complexity, systems incorporating electric motors have heretofore been favored by the petroleum industry because of their ability to achieve, even when the motors are of a relatively small size, a commercially acceptable rate of delivery of the liquid to the metering dispensers. In the latter connection, systems of the type in question must be capable of delivering from approximately 25-30 gals. per minute, which should be understood to represent a commercially acceptable delivery rate as that term is used herein.

Systems using fluid motors offer considerable advantages over those employing electric motors from the viewpoints of safety, complexity and also economy, particularly in the latter regard if capable of employing as motive fluid the compressed air available in virtually all vehicle service stations. A commercially acceptable delivery rate cannot, however, be readily achieved by a system using a fluid motor in lieu of an electric one of comparable size. Achievement of the foregoing requires, first, that the fluid motor and its related components be of a highly compact and efficient design and construction, since the foregoing necessarily include valve assemblies and the like not required by electric motors. Secondly, and of equal if not greater importance, the problem of freezejamming of the motor, during the high-speed operation thereof required for the system's production of a commercially acceptable delivery rate, must be overcome. Such problem arises from the tendency of moisture within the compressed air or other motive fluid to solidify upon expansioncooling thereof within the motor, and becomes increasingly severe as higher motor speeds are sought. Finally, the solutions devised to the aforesaid problems of compactness, efficiency and freeze-jamming must be compatible with and directed toward the realization of an overall pumping system which renders reliable operation with a minimum amount of maintenance and attention over prolonged periods of time, and which is therefore economical from the viewpoints of maintenance and use as well as that of initial cost.

SUMMARY OF THE INVENTION With the foregoing in mind, the present invention provides a highly efficient, compact, durable, economical and safe system particularly adapted for pumping gasoline and similar liquid hydrocarbons at commercially acceptable delivery rates from a storage tank to one or more metering dispensers at a vehicle service station, which system employs a fluid motor capable, during high-speed operation and without freezejamming, of using as its motive fluid the compressed air available in virtually all vehicle service stations.

In a preferred embodiment of the invention hereinafter described, the same includes a high-speed fluid motor compactly arranged in axial alignment and cooperative combination with a reciprocating pump and a motor operating valve assembly of novel construction. Intake and discharge lines of the pump respectively communicate with a storage tank and at least one metering dispenser. Compressed air from a conventional source such as found at a vehicle service station is automatically and continuously treated as it is conducted through a suitable conduit to the fluid motor and its valve assembly to prevent freeze-jamming of the latter during its high-speed operation. The air is treated by passing the same in a desired manner through an antifreeze solution contained within a chamber arranged in series with the aforesaid conduit leading to the fluid motor. Preferably the air is also passed through a heating unit which is additionally provided in series with such conduit at a location upstream from the aforesaid antifreeze tank. Treatment can, however, consist of simply passing the air through a heating unit without the use of the antifreeze tank, provided that the heating unit is mounted in close proximity with and adjacent to the fluid motor and its valve assembly. The present system preferably also includes, in the pump discharge line leading to the metering dispenser, expansion-chamber means for so dampening the pulsating flow from the pump means as to thereby insure a relatively uniform flow to the metering dispenser.

Other features and advantages of the invention will be in part apparent and in part pointed out hereinafter in the following specific description of a preferred embodiment thereof, which should be read in conjunction with the accompanying drawings, in which:

FIG. 1 is a partially diagrammatic elevational and sectional view of a pumping system embodying the invention;

FIG. 2 is an enlarged perspective view of a combined compressed air operated motor and pump of the system of FIG. 1;

FIG. 3 is an enlarged side elevational view of the pump cylinder and intake and discharge lines, with some parts being broken away for clarity;

FIG. 4 is a vertical section taken generally along the longitudinal axis of the system components shown in FIG. 2;

FIGS. 5 and 6 are enlarged vertical sections taken substantially along lines 5-5 and 6-6, respectively, through a portion of the valve assembly of the motor of FIG. 2;

FIG. 7 is an'enlarged perspective view of the motor operating valve assembly;

FIG. 8 is an enlarged horizontal sectional view, with parts broken away, taken substantially through components of the valve assembly of FIG. 7;

FIG. 9 is an enlarged side elevation of a portion of the pumps intake lines incorporating a pressure safety valve;

FIG. 10 is an enlarged vertical sectional view of the heating chamber used in the system of FIG. 1;

FIG. 11 is an enlarged side elevational view of a portion of the motor operating valve assembly incorporating a detent assembly of modified construction;

FIG. 12 is an enlarged perspective view of a detent release housing forming a part of the modified detend assembly of FIG. 1 1;

FIG. 13 is an exploded plan view of parts of the modified detent assembly of FIG. 12; and

FIG. 14 is a view similar to FIG. 1 of a part of the pumping system shown therein, illustrating a modified embodiment of the invention.

FIG. 1 of the drawing shows, in partially diagrammatic form, the system of the present invention in association with an underground storage tank 10, metering dispenser 1 1 and an air compressor 14 such as would normally be found at a conventional vehicle service station. Tank 10 contains gasoline 15 or other liquid hydrocarbon adapted to be pumped as required to dispenser l l for dispensing through its delivery hose I2 into the fuel tank of a motor vehicle or some other container (not shown). Conventional metering dispensers such as that identified by the numeral 1 1 customarily have a delivery rate, and therefore an intake requirement, of up to approximately 35 gallons per minute. Compressor 14 may be and preferably is of a standard two-horsepower type usually employed to provide compressed air, at pressures in the range of about 50-l30 p.s.i. for the inflation of pneumatic tires. It is of course understood that at a particular location more than one metering dispenser 1 1 and a different source of compressed air or other motive fluid might be provided, and that in its above-identified aspects FIG. 1 is only intended to illustrate one preferred application or use of the present pumping system.

Such system generally includes, as shown in FIG. 1, pump means 20 having an intake line 120 communicating with storage tank and a discharge line 124 communicating with dispenser 11; fluid-motor means including a motor 50 and associated valve assembly 70 operatively associated with pump 20 and connected by a conduit 152 to the reservoir of air compressor 14; means including a chamber 150 or a heating unit 140 or both arranged in series with conduit 152 for so treating the compressed air conducted therethrough to motor 50 and valve assembly 70 as to prevent freeze-jamming thereof during high-speed operation; and, preferably, means in the form of an expansion chamber 13 interposed in pump discharge line 124 for dampening the pulsating flow from pump 20 and thereby insuring a relatively uniform flow of liquid 15 from tank 10 and to metering dispenser 11 during operation of the system. Chamber 13 may be of any of several well-known types which are commercially available for performing functions such as aforesaid. The remaining components of the system are described in detail below.

Referring now also to FIGS. 2-4 of the drawings, pump is of the reciprocating double-acting type and includes a pumping cylinder 22 and opposed cylinder heads 29, 39 releasably clamped together by a plurality of bolts 32 (FIG. 2) extending therethrough. The interior of pump cylinder 22 (FIG. 4) is divided into two chambers 27, 28 by a piston 24. The pump intake line 120 (FIG. 3), leading from storage tank 10, connects to a cross fitting 130 that diverts the liquid being pulled therethrough into alternate ones of two suction lines 126 or 128 branching therefrom and respectively connecting with pump chambers 27, 28. An exteriorly threaded plug 131 (FIG. 4) seals the unused branch of cross fitting 130 and may be removed for insertion and cleaning of a filter screen 132 into the liquid flow path to filter out trash and other impurities that might be sucked from storage tank 10 by pump 20. Inlet check valves, 121, 123 (FIGS. 3 and 4) are mounted in suction lines, 126, 128 respectively to prevent backflow of liquid from pump 20 into tank 10. Between valves 121, 123 and pumping cylinder 22, outlet lines 125, 127 branch respectively from suction lines 126, 128 and connect to pump discharge line 124. Outlet check valves 133, 135 respectively provided within lines 125, 127 prevent application of the pumps suction to discharge line 124.

A pump rod 26 is secured at one end to pumping piston 24 (FIG. 4) for reciprocation therewith axially of pumping cylinder 22. Pump rod 26 passes from cylinder 22 through cylinder head 39 and a stuffing box 38 secured to the cylinder head in sealing relationship to the rods periphery.

Air that might be drawn from the storage tank 10 or otherwise enter pump 20 could accumulate in the top of pump cylinder 22, thereby reducing the pumps operating efficiency. This problem is avoided by bleeder lines 25, which interconnect openings in the top of cylinder 22 with discharge line 124 (FIG. 3) via T-fitting 21 and line check valves 23 that prevent the suction of pump 20 from pulling on discharge line 124.

Fluid motor 50 and its valve assembly 70 are axially aligned with each other and with cylinder 22 and rod 26 of pump 20. Motor 50 includes a motor cylinder 52 (FIG. 4) having integral flanges 54, 56 extending radially outwardly from its opposite ends. Assembly 70 includes a valve block 72 having an outer wall 67 and an inner wall 69 (FIGS. 4 and 7) and containing motor operating valves subsequently described in detail. A disc shaped plate 65 is attached to wall 69 by any suitable attaching means, such as by bolts 96 (FIG. 7), and is similar in shape and size to flange 56 of motor cylinder 52. Flanges 54 and 56 on motor cylinder 52 have openings therein to receive fastening means 82 for demountably attaching flange 54 to cylinder head 39 and flange 56 to plate 65 of valve block 72. Pump rod 26 projects into motor cylinder 52 and is secured to motor piston 58, which is similar in appearance to pump piston 24 and divides motor cylinder 52 into two chambers, 66, 68. Since rod 26 is secured to both pumping piston 24 and motor piston 58, reciprocation of the latter correspondingly reciprocates the former and operates the pump.

Motor piston 58 is reciprocated by compressed air that has been specially treated in a manner discussed more fully hereinafter. The air is directed to first one and then the other of chambers, 66, 68, while the chamber opposite thereto is being exhausted, both distribution and exhaust of the compressed air being accomplished by motor operating valve assembly 70.

The high-speed operation of motor 50 makes lubrication thereof highly desirable. This may be accomplished by the introduction of a suitable lubricant, such as weight transmission oil, into lubrication passages 51 and 53 extending respectively through flanges 54 and 56 and communicating with chambers 66 and 68 of motor cylinder 52 (FIG. 2). In practice, it has been found that the addition of about one pint of the aforementioned oil to each chamber of motor cylinder 52 will provide satisfactory lubrication for the parts therein without interfering in any way with the motors operation. Removable plugs normally seal passages 51, 53 and also drain passages 55, 57 (FIG. 4) which are respectively provided through the bottom edges of flanges 54, 56 to permit discharge of the lubricant from chambers 66, 68 when replacement thereof is desired.

The end section of pump rod 26 projecting into motor cylinder 52 has a longitudinal recess 59 therein that is enclosed by a cap 74 threadably attached to the pumps terminal end (FIGS. 4, 7 and 8). An opening 75 in cap 74 and axially aligned with pump rod 26 slidably receives the shaft of a valveshifter rod 78 that protrudes into recess 59. An enlargement 76 on the end of rod 78 that protrudes into recess 59 prevents shifter rod 78 from slipping through opening 75 in cap 74, thereby forming a lost motion linkage between pump rod 26 and valve-shifter rod 78. The free end of valve-shifter 78, projecting out of recess 59 is slidably mounted through an opening 86 in a connector bar 79 and terminates in enlargement 77, all of which will be discussed in detail below.

Turning now to FIGS. 2, 5 and 6 of the drawings, valve block 72 of motor operating valve assembly 70 has two horizontal valve-guiding bores 92, 94 extending longitudinally therethrough in parallel relationship to the projected axis of pump and rod 26 and on opposite sides thereof. The opposite ends of the aforementioned valve guides are of enlarged diameter and are tapped to threadably receive exten'orally threaded plugs which form therewith sealed valve chambers 88, 89, 98 and 99. The two plugs associated with chambers 89, 99 are each of solid construction, while those associated with chambers 88, 98 have axial bores respectively receiving valve stems 81, 91 projecting therethrough and provided with O- ring seals 71 fitted into peripheral grooves 73 thereon. Valve stems 81, 91 (FIGS. 7 and 8) project through the aforementioned plugs, out of valve block 72 and into chamber 68 of motor cylinder 52 and detachably connect to connector bar 79 for a purpose to be described later.

The inner faces of valve chambers 88, 89, 98 and 99 are counterbored and suitably finished to provide seats for two induction valves 85, 95 and two eduction valves 87, 97, all of which are of the poppit type. Valves 85, 87 are carried by valve stem 91 and are disposed within chambers 99, 98 respectively, while valves 95, 97 are carried by valve stem 81 and disposed within chambers 88, 89 respectively. The valves on each valve stem are so spaced from each other that reciprocating movement of the stem simultaneously seats or closes one valve and unseats or opens the other. Induction valve 85 and eduction valve 97 are adapted to be opened and closed together, as are induction valve and eduction valve 87. Passages 61 and 62 are bored in valve block 72 are connect with valve induction chambers 88 and 99, having the outer ends thereof tapped to threadably receive the compressed air induction line 152. Eduction passages 63 and 64 are bored in valve block 72 to communicate with the eduction chambers 89 and 98 through valve ports 101 and 102 and are likewise tapped for threadably receiving eduction lines 154, which may terminate in any type of suitable mufi'ler 156 (see FIG. 2).

Valve guide 94 with induction chamber 99 and eduction chamber 98 form a valve box 90 that communicates with motor chamber 68 by means of passages 106 and 107 provided in valve block 72 and connected by suitable threaded fittings to one end of air line 112 (FIG. 2). The other end of air line 1 12 communicates with chamber 68 through passage 114 (FIG. 4) in flange 56 of motor cylinder 52. Similarly, valve guide 92 (FIG. 5) with chambers 88 and 89 form a valve box 80 communicating with motor chamber 66 through passages I08 and 109, air line 116 and passage 118 (FIG. 4) in flange 54.

Returning to FIGS. 5 and 6 of the drawings, O-rings 83 positioned on valve stems 81, 91 in peripheral grooves 93 provided therein seal the valve guides 92, 94 so as to prevent leakage between the chambers 98, 99 or 88, 89 at opposite ends thereof. Lubrication passages 104 are bored in the side of valve block 72 and communicate with valve stems 81, 91 between the aforementioned C ring seals. The outer ends of passages 104 are tapped to receive lubrication fittings 105 (FIG. 2) for the introduction of a suitable lubricant, such as graphite, therein.

Valve stems 81, 91 extend from their respective valve boxes 80, 90 through the plugs sealing valve chambers 88, 98 and into motor chamber 68, where the ends thereof attach to connector bar 79, equidistantly on opposite sides of valve shifter rod 78. As hereinbefore described, connector bar 79 has an opening 86 therein through which passes valve-shifter rod 78, the free end of which terminates in enlargement 77 (see FIGS. 4, 7 and 8). Slidably mounted on shifter rod 78 between enlargement 77 and connector bar 79 is a coil compression spring 162, while a similar coil compression spring 164 is slidably mounted on shifter rod 78 but on the opposite side of connector bar 79, between bar 79 and cap 74. Caps 166, slidably mounted on valve-shifter rod 78, are fastened to opposite ends of compression springs 162 and 164, holding said springs in concentric alignment with the longitudinal axis of shifter rod 78. Detent arm 168, cantileverly mounted to wall 69 of valve block 72, projects over connector bar 79 and supports a downturned head 171 having a recess 173 therein. A recess 175 in the top edge of connector bar 79 registers vertically with recess 173 of the downturned head 171. Detent balls 177 are forcibly held in recesses I73, 175 by a detent compression spring 179 which urges said detent balls apart. In the preferred embodiment of the invention, a second detent arm 168A, having a compression spring 179A and detent balls 177A, representing a mirror image of the detent assembly first described, extends from wall 69 in a position beneath connector bar 79 (FIG. 4). A recess 175A, located in the bottom edge of connector bar 79 receives a detent ball 177A, held therein by compression spring 179A in the same manner as hereinbefore described in connection with detent arm 168. Satisfactory results have been realized in some instances by using only one detent arm and assembly, such as for example detent arm 168 located above connector bar 79; the use of two of them, while preferable, should therefore not be viewed as absolutely essential. The detent assembly or assemblies, the connector bar 79, and the valve-shifter rod 78 with compression springs 162 and 164 thereon, form a snap action mechanism, the operation and purpose of which will be described.

Operation of the motor operating valve assembly 70 can now be explained in light of the preceding description and with reference to FIGS. 4-6. When valve stems 81, 91 are reciprocated toward outer wall 67 of valve block 72 to a first position wherein valves 85, 97 are open and valves 87, 95 are closed, the treated compressed air is distributed to motor chamber 68 through induction valve chamber 99 and air line 112, while motor chamber 66 is being exhausted through eduction valve chamber 89 and air line 116. The result thereby obtained is for motor cylinder 58 to be pushed by the air pressure toward pump 20. As cylinder 58 thus moves (see FIG. 4 of the drawings), cap 74 engages enlargement 76 of valve-shifter rod 78 and pulls it toward pump 20 also. Compression spring 162 is pulled against connector bar 79 by enlargement 77, on the opposite end of shifter rod 78, pulling against cap 166 until the pressure applied by compression of spring 162 is sufficient to overcome the force of detent springs 179 and 179A holding the connector bar 79 and valve stems 81 and 91 in position, at which time the connector bar 79 is pushed toward pump 20 causing valve stems 81 and 91 to snap into a second position from wall 67 and toward wall 69 of valve block 72. Now valves 85 and 97 are closed with valves 87 and open (this being the position of the valves as shown in FIGS. 5 and 6 of the drawings), thereby reversing the distribution and exhaust of compressed air to motor chambers 66 and 68 and causing motor piston 58 to move toward valve block 72. This causes cap 74 to engage compression spring 164 and push it against connector bar 79 until the pressure thereof overcomes the pressure of detent springs 179 and 179A, snapping the motor operating valves back into their first position whereupon the cycle is repeated.

Compressed air, preferably air compressed to a pressure of between 50 to p.s.i., actuates motor piston 58 of air motor 50, thereby causing pump 20 to operate because of the pump rod 26 linkage therebetween. Before its introduction into valve block 72, the compressed air is first treated to avoid the problems of freezing and jamming heretofore experienced when attempts were made to operate the pump at commercially acceptable speeds. This treatment may consist of passing the compressed air through an upstanding chamber containing alcohol, which may be in the form of an antifreeze solution. The treatment may also include heating the air before passing it therethrough. It is believed that heating the compressed air, while having some beneficial effects with regard to the airs moisture content, increases its propensity to entrain vapors from the antifreeze chamber, thereby increasing the effectiveness of the antifreeze treatment in overcoming freezing and jamming of the motor with the problems attendant thereto.

The aforementioned treatment means, namely that of passing heated compressed air through an upstanding chamber containing alcohol, is considered to be the preferred embodiment for the practice of this'invention. However, the continued effectiveness of this means at preventing the air motor and valve assembly from freeze-jamming is dependent upon the periodic supply of alcohol solution to the chamber as vapors therefrom are carried out by the compressed air.

It has been found that satisfactory results may also be obtained and the upstanding alcohol chamber eliminated by shifting the position of the heating means so that the latter is in close proximity with and adjacent to the air motor cylinder (see FIG. 14). In the modified embodiment illustrated in FIG. 14, a cylindrical heating chamber 140, which will be described in the paragraph next following, is mounted in transverse relation to motor 50, approximately equidistant between pump 20 and valve assembly 70. While the exact positioning of chamber relative to motor 50 is not critical, it should be sufficiently close thereto so as to permit heat radiated from chamber 140 to be absorbed by motor 50, thereby tending to maintain the temperature of motor 50 at a level higher than otherwise. At the same time, however, the distance between chamber 140 and valve assembly 70 should be minimized to reduce the length of conduit 152 connecting therebetween, thereby reducing the amount of heat lost from the heated compressed air as it passes therethrough and into motor 50.

The means for heating the compressed air embraces a cylindrical chamber 140 (FIG. 10) enclosing an electrical heating element 142, which element is supplied an electric current by a conductor 144. The inner core of element 142 includes a heating coil 141, surrounded by insulating material 143. Compressed air, supplied by a conventional air compressor having a capacity of generating on the order of 50 to 135 p.s.i., is introduced into cylindrical chamber 140 through an inlet portal 146 adjacent the top edge thereof and exits through an outlet portal 148 located near the chambers bottom edge after circulating past and around heating element 142 and being heated thereby. A moisture accumulation bowl 149 having a drain cock 147 is located at the bottom of heating chamber 140 and provides a means for bleeding off accumulations of moisture when necessary. Bowl 149 accumulates those droplets of water which may be forced out of the air and against the inner sides of chamber 140 due to the cyclone effect of the compressed air swirling downwardly therein.

An upstanding chamber 150 (FIG. 1), charged with an alcohol containing solution such as antifreeze, is used to entrain vapors therefrom in the compressed and preferably heated air which enters the upstanding chamber 150 through a line 151 extending to the bottom of said chamber and below the surface of the liquid therein. Line 151 terminates in a spray nozzle type head 153 adapted to diffuse the air stream and cause the compressed air to bubble upwardly through the antifreeze solution, agitating the solution and entraining vapors therefrom in the process. The vapor-containing air then leaves chamber 150 at a point above the liquid level of the antifreeze through motor valve induction line 152, which projects into the top of chamber 150 through an opening 159 provided therein. A screen 155 angularly disposed in the top of chamber 150 prevents droplets, erupting from the surface of the agitated antifreeze solution, from inadvertently entering the opening of induction line 152 and being carried into the valve block 72 by movement of the compressed air therethrough. A partially transparent pipe 157 branching from the bottom of chamber 150 and extending parallel therewith the height of the chamber is closed at its upper end by a removable cap 158 and serves as a means for checking the liquid level of chamber 150 as well as a means for recharging the antifreeze from time to time as it is depleted through entrainment in the compressed air.

A pressure safety valve 180 (FIG. 9) may be used to protect the pump, metering dispenser 11, and related components and persons in the vicinity thereof, from possible injury should stuffing box 38 (FIG. 4) fail and allow a surge of pressure to enter the pump chamber 27. Safety valve 180 is installed in a safety bypass line 182 connected to pump intake line 126 so as to bypass line check valve 121. Under normal conditions safety valve 180 will close bypass line 182, thereby permitting operation of pump 20 in the normal manner; however, should stuffing box 38 fail in its function of sealing the opening for pump rod 26 through cylinder head 39, the surge of pressure from the motor actuating power fluid entering chamber 27 will cause safety valve 180 to pop open, thereby permitting the pressure to drain off into pump section line 120 and dissipate in storage tank 10.

When pump 20 is operated at speeds to deliver particularly small volumes, such as 5 gallons per minute or less, there may be some tendency for the motor valves to stop in an intermediate position, thereby causing the motor to stall. This undesirable result is avoided in the modified version of the detent assembly shown in FIGS. 11-13 of the drawings, wherein a detent release housing 181 is shown encircling connector bar 79 and slidably mounted on valve shifter rod 78. Detent release housing 181 comprises a top 191, bottom 192 and two side walls 193 and 194, connected along adjacent edges thereof to form a hollow box-like housing with open ends on opposed sides. Instead of having recesses 175 and 175A to receive one of the detent balls 177 and 177A (FIGS. 4 and 8), connector bar 79 has grooves 275 and 275A on the top and bottom respectively thereof, which grooves are in parallel alignment with the axis of shifter rod 78. The detent release housing 181 has, in sides 193 and 194 thereof, openings 187 adapted to register with the opening 86 in connector bar 79' for slidably receiving valve shifter bar 78 after housing 181 has been laterally slipped onto connector bar 79. Openings 178 the same as has been hereinbefore described. The vertical l dimension x of housing 181 is just larger than that of connec-.

tor bar 79 to enable housing 181 to slidably receive said connector bar, while the longitudinal dimension y is somewhat larger than the thickness of connector bar 79', corresponding to the aforementioned dimension, in order to permit some play in the movement of housing 181 on shifter rod 78 before it contacts connector bar 79' by the inner side of wall 193 .or 194.

With the preceding description of detent release housing 181 and the modifications attendant thereto in mind, its operation to overcome the problems of valve stalling associated with the lower operating volumes will be explained. Detent compression springs 179 and 179A, in the arrangement as hereinbefore described, exert pressure on connector bar 79' to hold valve stems 81 and 91 in either of their two operative positions, whichever the case may be, until suffcient pressure accumulates in compression spring 162 or 164 to overcome the detention and snap the valve stems into their opposite position. This is the same operation that has been previously described, however, the difiiculty arising at the slower speeds is believed to reside in the inability of compression springs 162 or 164 to generate sufficient pressure to cause valve stems 81 and 91 to snap before moving the valve stems just enough to open all of the valves at the same time, thereby stalling the air motor 50.

Detent release housing 181 overcomes this problem of stalling in the following manner. With valve stems 81 and 91 in the second position, as hereinbefore described, the valve connector bar 79' is pushed furthest away from wall 69 of valve block 72 and held in that position by the detent pressure pushing against housing 181 which, in turn, pulls the inner side of wall 194 against connector bar 79'. The play between the movement of connector bar 79' and housing 181 is represented by the gap existing between the inner side of wall 193 and the side of connector bar,79' adjacent thereto. As compression spring 164 is pushed toward connector bar 79', causing cap 166 to push against wall 193 of housing 181, representing a portion of the series of events that will shift valve stems 81 and 91 into their first position, the housing 181 is moved toward wall 69 until the gap between wall l93.and connector bar 79 is closed. When this has happened, the detent balls 177, resting in grooves 275 and 275A in connector bar 79' and openings 178 and 178A in housing 181 have been pushed toward wall 69 also by movement of the housing 181. This movement of the detent balls releases most of the detent pressure that compression spring 164 must overcome before it causes the valve stems 81 and 91 to snap into their first position. With wall 193 pressing against connector bar 79' and the detent pressure opposing the compression spring 164 substantially removed, the compression spring will then cause the valve stems to snap into their next position without the problem of stalling. The operation is reversed when air motor piston 58 reaches the opposite extreme of its movement causing valve shifter rod 78 to pull compression spring 162 against wall 194 of the detent release housing 181.

While the preceding description has disclosed a specific embodiment with modifications of this invention in its preferred form, it is to be understood that various changes in detail and arrangement may be made without departing from the spirit and scope of the invention, the scope of the invention being defined in the claims.

What is claimed is:

1. In a high-speed fluid motor adapted to be operated by a power fluid such as compressed air furnished thereto by a first conduit means interconnecting said motor to a suitable power fluid source, an improved motor operating valve assembly for receiving said power fluid from said first conduit means and operatively distributing said fluid to said motor through a second conduit means, wherein said motor operating valve assembly comprises:

a valve block detachably mounted to said motor and containing a pair of horizontally spaced, parallel valve boxes therein, each of said valve boxes including an induction and an eduction valve chamber interconnected by a valve stem guide; said valve block further having induction and eduction passages operatively connecting said first and second conduit means to selected ones of said induction and eduction valve chambers;

a pair of double acting valves reciprocally mounted in corresponding ones of said valve boxes, each of said valves including a valve stem having a pair of oppositely disposed valve heads fixedly mounted thereon, said double acting valves being adapted to reciprocate between two operating positions and selectively open and close said induction and said eduction valve chambers; and

shifting means responsive to the operation of said motor for reciprocating said double acting valves in said valve boxes to operatively distribute said fluid to said motor, said means including:

i. detent means adapted to maintain said valves in either of said two operating positions until positively displaced therefrom;

ii. connecting means having lost motion linkage with said motor for reciprocating said valves between said operating positions, said connecting means being adapted to reciprocate both of said valves as a unit.

2. Apparatus as in claim 1, wherein said detent means includes a detent release housing slidably mounted on said connecting means and in operative relationship therewith to release said detent means prior to movement of said valves by said connecting means for operation of said motor at speeds below those tending to cause said motor to stall.

3. Apparatus as in claim 1, including a treating means connected with said first conduit means for heating the power fluid furnished to said motor operating valve assembly by said first conduit means.

4. Apparatus as in claim 3, wherein the treating means comprises means for heating the power fluid furnished to said motor operating valve assembly by said first conduit means, the location of said heating means relative to said motor means being such that heat radiating from said heating means will be absorbed by said motor means and heat loss from said heated power fluid conducted through said first conduit means from said heating means to said motor operating valve assembly, due to the distance of travel therethrough, will be minimized.

5. Apparatus as in claim 4, wherein said means for heating the power fluid comprises a generally cylindrical chamber, a heating element concentrically mounted within said chamber and forming with said chamber an annular jacket extending longitudinally thereof, said cylindrical chamber having an inlet adjacent one end thereof for the introduction of power fluid from said source into said annular jacket and having an outlet adjacent the other end for the discharge of said fluid therefrom, said power fluid being adapted to pass through said annular jacket in a cyclone fashion, eliminating droplets of moisture therefrom. 

1. In a high-speed fluid motor adapted to be operated by a power fluid such as compressed air furnished thereto by a first conduit means interconnecting said motor to a suitable power fluid source, an improved motor operating valve assembly for receiving said power fluid from said first conduit means and operatively distributing said fluid to said motor through a second conduit means, wherein said motor operating valve assembly comprises: a valve block detachably mounted to said motor and containing a pair of horizontally spaced, parallel valve boxes therein, each of said valve boxes including an induction and an eduction valve chamber interconnected by a valve stem guide; said valve block further having induction and eduction passages operatively connecting said first and second conduit means to selected ones of said induction and eduction valve chambers; a pair of double acting valves reciprocally mounted in corresponding ones of said valve boxes, each of said valves including a valve stem having a pair of oppositely disposed valve heads fixedly mounted thereon, said double acting valves being adapted to reciprocate between two operating positions and selectively open and close said inductIon and said eduction valve chambers; and shifting means responsive to the operation of said motor for reciprocating said double acting valves in said valve boxes to operatively distribute said fluid to said motor, said means including: i. detent means adapted to maintain said valves in either of said two operating positions until positively displaced therefrom; ii. connecting means having lost motion linkage with said motor for reciprocating said valves between said operating positions, said connecting means being adapted to reciprocate both of said valves as a unit.
 2. Apparatus as in claim 1, wherein said detent means includes a detent release housing slidably mounted on said connecting means and in operative relationship therewith to release said detent means prior to movement of said valves by said connecting means for operation of said motor at speeds below those tending to cause said motor to stall.
 3. Apparatus as in claim 1, including a treating means connected with said first conduit means for heating the power fluid furnished to said motor operating valve assembly by said first conduit means.
 4. Apparatus as in claim 3, wherein the treating means comprises means for heating the power fluid furnished to said motor operating valve assembly by said first conduit means, the location of said heating means relative to said motor means being such that heat radiating from said heating means will be absorbed by said motor means and heat loss from said heated power fluid conducted through said first conduit means from said heating means to said motor operating valve assembly, due to the distance of travel therethrough, will be minimized.
 5. Apparatus as in claim 4, wherein said means for heating the power fluid comprises a generally cylindrical chamber, a heating element concentrically mounted within said chamber and forming with said chamber an annular jacket extending longitudinally thereof, said cylindrical chamber having an inlet adjacent one end thereof for the introduction of power fluid from said source into said annular jacket and having an outlet adjacent the other end for the discharge of said fluid therefrom, said power fluid being adapted to pass through said annular jacket in a cyclone fashion, eliminating droplets of moisture therefrom. 